Improvement in treadles



2 Shets--Sheet No.4 120,461. iPamnxed 001. 31, 1871K.

UNITED STATES AI B. SHAW, OF MEDFORD, MASSACHUSETTS.

IMPROVEMENT IN TREADLES.

Specification forming part of Letters Patent No. 120,461, dated October 31, 1871; antedated October 18, 1871.

T0 all whom it may concern:

Be it known that I, AI B. SHAW, of Medford, in the county of Middlesex and State of Massachusetts, have invented an Improvement in Treadles, of which the iollowing is a full, clear, and exact description, reference being had to the accompanying drawing makin g part of this specication, in which- Figure l is a perspective view of a sewingmachine table with my improved treadle applied thereto. Fig. 2 is a sectional elevation, the parts being represented in a different position. Fig. 3 is a longitudinal vertical section on the line of Fig. 2. Fig. 4 is a transverse vertical section on the line y y of Fig. 3.

My invention relates to that class of treadles used in sewing and other light machines, lathes, 823e.; and consists in a rack-bar operated by the foot-plate, in combination with a cog-wheel, pawl, and iiy-wheel.

To enable others skilled in the art to understand and use my invention, I will proceed to describe the manner in which I have carried it out.

In. the said drawing, A represents a fly-wheel turning loosely on the shaft a, and having an elongated hub or sleeve, btextending over the greater portion of the shaft, as seen in Fig. 3, and to this sleeve b is permanently secured the pawl-case or pulley B, one side of which is covered by a circular plate, c, to the outside of which is secured a cog-wheel, d, with which engages a rack-bar, C, the lower end of which is attached to the foot-plate D, which is pivoted upon a rod, E, and is raised, after being depressed by the foot, by a spiral spring, e,- and thus, as the footplate is operated, the plate c is partially revolved or oscillated back and forth. The rack-bar is v supported and held in contact with the cog-wheel d by an arm or guide, f, which is secured to the shaft a. by a set-screw, the inner end of the arm serving to hold the plate c and cog-wheel d in place upon the shaft. To the inside of the plate c is loosely pivoted a pawl, g, of the form seen in Fig. 4, which is pressed toward the center by a light spring, 5, the width of the outer end 6 of the pawl being greater than the distance between the hub 7 of the box B and its rim 8, so that as the plate c is partially revolved in the direction ofthe arrow, Fig. 2, the portion 6 of the pawl is wedged between the hub 7 and the rim 8, and the ily-wheel is revolved thereby; while, when the plate c is rotated in the opposite direction, the friction ofthe pawl is relieved, so as to allow the fly-wheel to continue its revolution independently of the plate c, and when pressure is again applied to the foot-plate the fly-wheel receives an additional impetus.

What I claim as my invention, and desire to secure by Letters Patent, is

The rack-bar (l, operated by the spring footplate D, in combination with the cog-wheel d, pawl g, and iiy-wheel A, operating substantially in the manner and for the purpose set forth.

Witness my hand this 23d day of March, A. D. 1871. y

Witnesses: AI B. SHAW.

P. E. TEscHEMAcHER, W. J. CAMBRIDGE. (67) 

